Small size ignition device



May 14, 1968 K. LEHMANN ET AL SMALL SIZE IGNITION DEVICE I Filed Nov. 8, 1966 ,FIGLZ FIG.3

United States Patent Office 3,382,804 Patented May 14, 1968 2 Claims. c1.1o2--10.z

ABSTRACT OF THE DISCLOSURE The invention relates to a small size ignition device for igniting the detonators of propellent and explosive charges, which is particularly handy and yet of reliable function, and which does not require any outside current sources. The said ignition device utilizes a draw string drive of a type which activates the alternator on both the forward and return run.

The prior art Condenser ignition devices are known as such. These devices contain their own generator, which is usually activated by a push-rod or a crank. These devices require a relatively great mechanical expenditure, such as a relatively large gear unit or drive for the push-rod, thereby rendering the entire apparatus rather large in size and unwieldly.

It has already been suggested to equip a portable electrical ignition device with a draw string drive which, however, calls for trackboards to be able to draw the draw string out sufiiciently far. Therefore, this ignition apparatus is not usable for those cases of application where it is required to have a small, handy device always at ones disposal.

Objects of the invention An object of the present invention is the development of a small size ignition device independent of outside current sources for igniting the detonators of propellent and explosive charges consisting of a condenser ignition device and a source of electrical current supplying the condenser wherein the improvement comprises an alternating current voltage alternator and a draw string drive which activates said alternator on both the forward and return runs, as said source of electrical current.

A further object of the present invention is the disposal in the small size ignition device of the invention of a control lamp disposed in series to the ignition terminals for testing purposes.

These and other objects of the invention will become more apparent as the description thereof proceeds.

Description of the invention The ignition device according to the invention is, in comparison to the prior art devices, producible in the smallest dimensions without essentially any projecting parts, independent of outside current sources, yet possessing an assured function.

It comprises a well known condenser ignition device and it is characterized by an alternating current alternator in connection with a draw string drive of a type which activates the alternator during both the forward and return run. Another advantageous feature of the invention is that the device has in parallel relation to the ignition terminals a control lamp for testing, when the ignition circuit is not connected.

The manner in Which this device functions is shown in detail in the attached drawings.

FIGURES 1 and 2 show the small size ignition device with the draw string drive.

FIGURE 3 shows the circuitry of the condenser ignition device.

As shown in FIGURES l and 2, a spring housing 2, connected with a drive gear 3 and a cord pulley 6, is mounted on a shaft 7. The spring 1 in spring housing 2 is rigidly connected at its outer end with the housing 2 and the other end is securely connected with the shaft 7. On drawing the draw string 8 from the cord pulley 6, the drive gear 3 rotates and causes the alternator 5 to rotate by action of pinion 4. Simultaneously, the spring 1 is subjected to tension and upon release of the draw string 8, the spring 1 forces the drive gear 3 and with it the alternator 5 by action of pinion 4 to rotationin the reverse direction.

As it can be perceived both direction of the draw string movement are utilized for the activation of the rotor of the alternating current alternator. Therefore, the draw string can be especially short in length. During the forward pull of the draw string, the permanent magnetic rotor of the alternator 5 is put into rotation, while at the same time the pre-tensioned spring is tightened. The retroactive force of this tightened spring 1 is greater than the torsional moment of the alternator 5 forcing the alternator to rotate as the spring unwinds. Thus the alternator also generates an alternating current voltage in a reversed rotational direction when the draw string is being returned by action of the spring.

The alternating current voltage activated by the alternator during the forward and return run of the draw string is utilized for the charging of the condenser, as will be described in detail in the following.

The circuit system of the condenser ignition device is illustrated in FIGURE 3. The alternating current voltage supplied by the alternator G is rectified across a voltage doubler (C 6,, G and boosts the condenser C to the required ignition impulse voltage.

At attaining this voltage, a gas diode D is ignited and the condenser now transfers its stored-up energy to a connected external circuit ZK through the output terminals. R is a discharge resistor, disposed in the condenser circuit, for the reduction of any remaining voltages of the condenser. Furthermore, a glow-lamp (GL) with compensating resistance R is mounted in parallel relation to the ignition terminals. 'Ihis glow-lamp lights up brightly when the impulse transmitter is activated when not connected to an outside circuit ZK, and it indicates the functionability of the device. Resistance R acts as final resistance in case the ignition device is operated without the ignition circuit.

By means of the construction of the ignition apparatus of the invention as described in the preceding, it is possible to manufacture a device which measures only x 55 x 30 mm. and weighs 200 gm. With the length of the draw string being only mm., this device attains a condenser impulse in the magnitude of mil'l-iwatt seconds. On the exterior of the device only the terminals and a small button for pulling the draw string are visible. For specific purposes, embodiment forms of still smaller measures are conceivable.

The preceding specific embodiment is illustrative of the invention. It is to be understood, however, that other ex-pedients known to those skilled in the art may be employed without departing from the spirit of the invention or the scope of the appended claims.

We claim:

1. A small size ignition system for detonator ignition of propellant and/ or explosive charges, said system comprising a condenser discharge ignition circuit and an alternating current source of electrical energy for condenser charging, wherein the improvement comprises an alternator and a spring-loaded, dual-direction actuated, draw string drive means connected to substantially continuously drive said alternator to provide firing circuit actuation.

2. The small size ignition system of claim 1 further comprising as an improvement therein, a test lamp.

References Cited UNITED STATES PATENTS 670,006 3/1901 Raymond 310--68 5 1,479,592 1/1924 Evans 31069 X 2,313,101 3/1943 Stuart 31069 3,037,148 5/1962 Gayler 31070 X BENJAMIN A. BORCHELT, Primary Examiner.

10 T. H. WEBB, Assistant Examiner. 

